Sylvania



Patented Dec. 16,1919.

L'. V. LEWIS.. RAILWAY SIGNALING SYSTEMlv APPLICATION FILED JULY 9. |919L |11 mm. @w L n AN@ ELS NNQM n 1 au@ my I d UNITED STATES PATENT oEEIcE.

LLoYn lv.-L1-:vvIs',`oF wILKINsBUnG, PENNsYLvANIA,'AssIGNoR To THE rUNION SWITCH a SIGNAL COMPANY; or. swIssvALn' BENNSYLVANIA', A conroRATIoNor PENN- SYLVANIA. f

RAILWAY SIGNALINGSYSTEM.

Speciiixvzation. of Let-ters Patent. Patented Dec, 16, 1919.

Application iiled July 9, 1919. Serial No. 309,712.

To all 'whom it may concern:

-l3e it known that I, LLOYD IJEw'IsL acitizen of the United States, residing at 711-4 kinsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements'in Railway Signaling Systems, of which the followp ing is a speeificatlon.

VMy invention relates to signahng systems for railways, and particularly to/ systems of the type comprising roadside signals for govermng the passage of cars and trains along the railway, and alternating current track circuits for controlling such signals.

' One object of my Invention Isthe provision of a novel and useful combination' of f apparatus whereby the signals may be reliably and effectively controlled by onlya minute amount of energy abstracted from thetrack circuits. The invention readily adapts itself, therefore, to signaling systems for railways the track rails of which are electrically continuous throughout, although it is not limitedy to signaling on a road of this type. t

I will describe one form of signaling system embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figure 1 is a View showing diagraminatically one form of signaling system embodyingmy invention. Fig. 2 is a fragmental view showing an alternative means which may be employed in lieu of the means shown in Fig. 1, for abstractingI `signal controlling energy from the track circuit.

Similar reference characters refer to similar parts in each of the views.

,Referring first to Fig. 1, the reference characters R and R designate the track rails of a railway over which traffic normally y moves in the direction indicated by the arrow. The track rails, in the system shown herein, are electrically continuous throughout. The railway here shown is of the type employing direct current for the propulsion of the cars or trains, and hence it is provided with a trolley wire or third rail T, and with a propulsion generator GD one terminal of `which is connected with the trolley wire'and the other terminal with ground.

The railway is divided into blocks by means of bonds, 2, 2, etc., of low impedance connected across the rails, there bem two bonds at each' junctionl of adjacent b ocks, separated by a short distance such that the impedance of the intervening lengths yof rails will prevent the iow of an appreciable amount of alternating track circuit current from block to block Only one complete block A--B is shown in the drawing, but it is 'understood that the apparatus shown in this block would be duplicated for a plurality of.

successive blocks, as indicated `by the a paratus illustrated for the ends of the b ocks llfin to the right and to the left of block Located at or near the'middle of the block A-B is a transformer U whose secondary is connected across the track rails, and whose primary is connected `with a transmission ine M to which .alternating signaling eurrent is supplied by a generator GA. 'This transformer is, then, the'soure of track circuit current for the block A-B. v i

Located adjacent the bond 2l is a coil f3 which is in inductive relation to the bond and toa short length of each rail near the bond,so that alternating current is induced in this coil due to the'current in the track' circuit. The energy induced in this coil is employed to control a signal controlling relay P, which relay comprises a rotor 27 and two stator windings 25 and 26. `One winding 26 isconstantly supplied with alternating current from the secondary 18 of a transl former L, the primary of which is connected across the transmission line M, while'the .other winding 25 is controlled by the track circuit current induced iii coil 3, It is obvious, however, `that when the track circuit Vcurrent is of a commercial value, the amount of'energy which is created in coil 3 will lie minute, and that conse uently this energy, cannot be applied dir'ect y tothe relay P if this relay is of reliable and rugged con? struction. For this reason, I interpose between the coil 3 and the winding 25 of relay P a'n ampli'erlof the electrontype, comprising'a vacuum bulb containing a filament 4, a plate- 5 and a grid 6 located between the two. The filament 4 is constantly heated by alternatin ary 8 of t e transformer La. One terminal of the coil 3 is connected with the grid 6 of an amplifier K through a Vcondenser 9,

whereas the'other terminal of the coil 3 is iconnected -with the filament 4 of this amplifier. ,As here shown, this latter connection is accomplished by connecting the terminal of thecoil with the middle point of the 'secoiidary'8 of transformer L, which serves to energize filament 4, the pui-'pose of this form of v:is

connection being to maintainl a constant average potential difference between` grid 6 and filamenti irrespective of the alternating potential difference across the filament. lhe

i purpose of the condenser 9 is, of course, to iiisu're that the potential on the grid 6 will 4 always be negative .with relation to the po'- tential of filament 4: in order to minimize the flow of electrons from the filament to the grid.- This grid circuit for lthe amplifier, that is, the circuit including coil 3, I will term a trackway circuit.

The amplifier K is provided with a plate circuit 7which includes a source of direct cur- -rent and winding 25 of the signal controlling relay l Pa. As here shown, the direct .current soureefor this circuit is the propul'4 sion generator GD, and the circuit is from. 'the trolley wire T, through wire 10, winding 25 of relay P and condenser 11 in multiple, wire 12, plate 5, filament 4, wires 13 and .14 in multiple, the two halves of secondary 48 in multiple, and wires 15 and 16 to. ground at pointl?, thence to generator GD. The local circuit comprising condenser ll'and. winding 25 of relay Pf# is tuned to resonance at the frequency of the track circuit current. The variations in potential between the filament f1 andthe grid 6 will, of course, cause variations of considerably greater magnitude in the current flowing in the plate circuit of the amplifier, and these variations are of sufficient amplitude to.v reliably control a rugged commercial relay.

amplifier K,

This relay is, of course, of a type adapted to respond to alternating current and not to direct current.

stantly.supplied with energy from transformeinL, the -relay may lie operated on about 0.02 watt supplied to winding 25- by If this relay were of a single winding type the entire energy to which were supplied by the amplifier K, the en# ergy required from this ,amplifier would be.

about`2 watts,J and this would not be coinmereially practicable because it 'would require an excessive track circuit current or' an excessive' number of` turns in coil 3f. i

It follows from the foregoing that when current supplied from a secoiid- P opens.

By providing relay P with-two windings one of which is con-` track circuit current froni transformer U flows through the bond 2, it will cause relay P to be energized, but that when the ,sup ply of track circuit current to the bond 2' is discontinued relay P will become denergized.

The right-hand end of block A-B is provided with 'a coil 3b, anampliier Kb, and a relay P", these parts being arranged and connected in the same manner as the cor- 'splonding parts at the left-hand. end of the oc t.

Located at the entrance end of the blockn .A-B is a signal SB, which'is controlled by h oth relays l".x and Pb. The circuit for this signal is from secondary 18 of transformer L through wires 19 and 19, contact 20 of .relay PI, wire 21, contact 22 of relay P,

wire 23, operating mechanism of signal SB,

and wires 24', 2liu and 24" to the secondary 18 of transformer La. It follows, therefore,l that signal S will indicate proceed? when both relays P and l?b are energized, and

,stop,when either or botlrof these relays shunts the greater part of the current from the bond 2b and the track rails adjacent this bond, so that relay Pb becomes denergizcd,

'. whereupon signal S moves to y`the stop position. As the train approaches-the point at which transformer U -is connected with the rails, the amount of track circuit current flowing Vto the left from this point of connection becomes reduced to such value that relay After the train passes some distanceheyond'the point at which transformer U is connected with the rails," relay Pl again becomes energized, but, signal S remains in the stop position iintilielay P becomes-.energized, and this, of course, does not occur until the entire train passesout of block A--B.I

Referring now to Fig. 2, in the modification here shown, the trafekway'circuit is connected with the track circuit directly instead of inductively as in Fig. 1. That is, the grid and filament of each amplifier 'are connected directly with the track rails at points V25 and 25a which area short distance from the low impedance bonds. In

this form of the invention the drop in potential along the track rails from point 25 through the bond to point 25a`is utilized to create an alternating difference of potential between the filament and the grid of the amplifier. .The result isthe same as that 'secured with the apparatus shown in Fig.

1. vVarious other forms of` apparatus may be utilized to create a difference of potential in the 'grid circuit of each amplifier, due to 4 the track, circuit current. l

Although Iliave herein lshown and de- 'scribed onlytwo forms of apparatus e111-, 'bodying my invention, it is understood that various changes and modifications. may bemade therein within 4the scope of the ap pended claims without departing from the spiritan'd scope of my invention.

' Having thus described my invention,what I claim isz, f

1. A railway signaling .system for railways, the track railsof which areelectrically continuous throughout, comprising bonds of negligible 4impedance connected across the r'ails at intervals to form blocks, a source of alternating-signaling current connected across the rails at substantially the middle of each block and forming a closedtrack circuit withthe bond at each end of the block,

a fixed coil in inductive relation to a portion of each track circuit, a relay for each coil and located in the trackway, an electron amplifier interposed between -each coil and the corresponding relay, and roadside signals controlled by said-relays.' l

2. A signaling system for'railways for whichv the propulsion energy is direct current, comprising track. rails, a track circuit including said rails and a source of alternating current; anelectron amplifier located in alternating current transmission line extending along said railway, a track circuit su plied from said transmission line and inclu ing the track'rails of said railway; an electron amplifier located 'in the trackway and i having a filament, a grid and a plate; a

trackway circuit receiving a minute amount of energy from said tradkcircuit and connected with lsaid filament and grid, means for supplying current to said filament from said transmission line, a plate circuit for said amplifier connected with 'the trolley wire and with ground and including a relay, and a' roadside signal controlled by said relay. h

4. In combination, a railway track, an alternating current transmission line extending along said track, a track circuit supplied from said transmission line and including the track rails of the railway, a trackway circuit icceiv-ing'a minute amount of energy by said relay. 5. In combination, a railway, the propul- V from said track circuit; an electron am- 65 plier located in thetrackway and having a. filament, a, grid, and a plate; the terminals of said trackway circuit being connected with said filament and grid, means for sup- 1 A/plying current to said filament from said transmission line, a plate circuit forsaid amplifier includiirfggd a source of 'direct current and a. relay, and a roadside signal controlled sion energy for which is directcurrent, an alternating current transmission line extending along said railway, a track circuit supplied from said transmission line and including the track rails of said railway.; van electron amplifier located in .the trackway and having a filament, a grid and a plate; a

' t'rackway'circuit receiving a minute amount of energ from said track circuit and connected with the filament and grid of said ai'n- 85 plifier, a transformer whose primary is connected with said transmission line and whose secondary is connected with the filament of said amplifier; a plate circuit for said amplifier comprisinol a connection from a trolley wire to the p ate, and a connection from the middle point ofthe secondary of saidvtransformer to ground; a relay included in said plate circuit, and a roadside 'signal controlled by'said relay. 95

6. In combination, a railway track, an allteriiating current transmission line extending along said track, a track circuit supplied from said transmission line' and'including the track rails of said railway; an electron amplifier located in the trackway and having a filament, a grid, and a plate; a transformer whose primary 4is connected with) said transmission line and whose secondary is connected with the filament of said amplifier, a los trackway circuit receiving a minute amount of energy from' said track circuit and havin its terminals connected with the grid of sai amplifier and with the middle point of the secondary of lsaid transformer, a plate circuit for said amplifier including a source of direct current and a relay; and a roadside signal controlled by said relay.

7. In combination, a railway, the propulsionl energy for'which is'direct current, an 115 alternating current transmission line extending a'lbng said railway, a track circuit supplied from' said transmission line andj'including the track rails of the railway ;`1 an electron amplifier located in the trackway 1.20

and having a filament, a grid, and a plate'r a.

transformer whose primary is connected with said transmission line and whose secondary is connected with the filament of said amplifier, a trackway circuit receiving a y minute amount of energy from said track circuit and having its terminals connected respectively with the grid of said amplifier and with the middle point of the secondary of said transformer; a plate circuit for said amplifier comprising a connection from the plate to the trolley wire, and a connection from the middle point of the Ysecondary of said transformer to ground; said plate circuit including a relay, and a roadside signal controlled by said relay.

S. A railway signaling system comprisin 'l .-1 track rails, a track circuit comprismg sai and a source of alternating current, a -rackway c1rcu1t receivlng a minute amount energy from said track c1rcu1t, a relay 1ocated in the tra'ckway and comprising two windinsone of which is constantly'energizcd from said surce of alternating" current, amlplifying means interposed between said trac i of said relay, and a roadside signal controlledby said relay.

In testimony whereof I affix my .signature in presence of two witnesses. LLOYD V. LEWIS. lWitnesses: v 1

A. HERMAN WEGNER, i

E. P. CHUM.

isl

way clrcuit and the other winding 

